1. Field of the Invention
The present invention relates to a fuse holder fixing a fuse, and more particularly to a fuse holder preferably used for fixing a fuse for a heavy current.
2. Description of the Related Art
A fuse having a heavy capacity (approximately 300 A) used for an electric automotive vehicle in a related art comprises a cylindrical fuse and L-shaped terminal portions connected to both side portions of the fuse body, and a mounting hole is formed in each of the fuse terminal portions.
On the contrary, in fuse holders to which the fuse is fixed, one end is fixed to a connecting box body by a mounting bolt. The other ends (upper surface ends) of the fuse holders are formed as a fixing surface. Further, a screw hole open to the fixing surface is formed on each of the fuse holders.
Then, in a state of fixing the fuse holders to the connecting box body, the end portion of the bus bar is mounted on the fixing surface of one of the fuse holders, one of the fuse terminal portions of the fuse is overlapped thereon, and the fuse mounting bolt is inserted thereinto so as to be meshed with the screw hole. As in the same manner, the end portion of the bus bar is mounted on the fixing surface of the other of the fuse holders, the other of the fuse terminal portions of the fuse is overlapped thereon, and the fuse mounting bolt is inserted thereinto so as to be meshed with the screw hole. Finally, by fastening the fuse mounting bolt, the fuse is fixed to the fuse holders and is fixed to the connecting box body.
However, in the fixing structure for the fuse mentioned above, since each of the fuse holders which is separated into two portions is fixed to the connecting box body by the mounting bolt, a pitch accuracy of the screw holes between the fuse holders is deteriorated, so that a position adjustment is required between the fuse holders at a time of screwing the fuse terminal portions of the fuse. Accordingly, there is a problem that a mounting operability is bad at a time of mounting the fuse to the connecting box body.
In order to solve the problem, Japanese Utility Model Unexamined Application Laid Open No. 7-41947 and No. 5-69848 suggest that the end of the bus bar is directly screwed to the connecting box body together with the terminal portion of the fuse without using an independent fuse holder.
In the fixing structure for the fuse described in Japanese Utility Model Unexamined Application Laid Open No. 7-41947, in a pair of terminal portions disposed in both sides of the fuse body of the fuse, the end portion of the bus bar is overlapped on the insulating plate, the terminal portions are respectively overlapped thereon and the terminal portions of the fuse fixed onto the insulating plate together with the bus bars by the screw. In accordance with this structure, since the fuse holder is not used, a time and labor for mounting the fuse holder can be saved and it is unnecessary to adjust the pitch between the terminal portions, a good operability for mounting the fuse can be obtained.
In the fuse mounting structure described in Japanese Utility Model Unexamined Application Laid Open No. 5-69848, as in the same manner as that of the publication mentioned above, the end portion of the bus bar and the terminal portion of the fuse are directly screwed on the insulating plate in an overlapping manner, so that the fuse is directly fixed to the insulating plate without using the fuse holder so as to be electrically connected to the bus bar. In this structure, the time and labor for mounting the fuse holder can be saved and the good operability for mounting the fuse can be obtained.
However, in each of the structures mentioned above, since the fuse is fixed onto the fuse holders and each of the insulating plates together with the bus bar in a bare state, there is a risk that at a time of assembling the other electric parts on the connecting box body or on the insulating plates, the other electric parts are erroneously brought into contact with the fuse or an unreasonable force is given to the fuse so that the fuse is broken.
Further, since the electrical connecting portion with the bus bar is in a bare state, when a electrically conductive foreign substance is erroneously entered into the connecting box body, there is a possibility of forming an electrical connection.